Where does VisualStudio store the region states?

Question

Has anyone ever wondered where VisualStudio stores the states of regions in the source code (expanded or collapsed?). As far as I can see they are not stored in the solution, the project or the source file...

Answer 1

All of those types of settings (region collapse state, solution explorer open/close state, currently open files, etc...) are stored in the .suo file that resides next to your solution file.

If you delete the .suo file, you will lose this state, but not lose anything pertinent to the actual solution/code. Many people exclude this file from source control as it contains user-specific data.

Answer 2

They are stored in the .suo file.